Cabinet Chief Jorge Capitanich forecast on Dec. 19 that the overall fiscal deficit would be 137 billion pesos, equivalent to 3.3 percent of GDP. Private economists were expecting an even higher figure.

The latest data showed a sharp fiscal deterioration in December, with the primary deficit, which does not include debt interest payments, widening 17.3 percent from a year earlier to 23.336 billion pesos.

The primary deficit all of 2014 was 38.561 billion pesos. Capitanich had said the primary deficit for last year would come to 56 billion pesos.

Financial markets closely follow the primary budget because it represents a country's ability to honor its financial commitments. Argentina tipped back into default in July after it failed to settle a long-running legal battle with U.S. creditors over unpaid debt. (Reporting by Jorge Otaola; Writing by Richard Lough; Editing by Chizu Nomiyama and Lisa Von Ahn)